Has anyone tried a throttle body spacer (not an insulator) on the 3.5l to fatten the midrange torque? The spacer increases the plenum volume slightly, and is fitted between the throttle body and the mounting flange. They are usually about 15-20mm thick. I've used one on my Jeep and seen an improvement in economy, so I'm wondering what experiences people have had with their Magnas.

Ken

An interesting idea. It would require a fairly large spacer to make too much of a difference I would think...

Most people increase the plenum volume by replacing it with a big fat piece of aluminium pipe :)

Cheers
Heath Young

The spacer for the Jeep improved fuel economy by 1 l/100km. Which doesn't sound like much, but it all adds up. The beauty of this mod is that it is a simple bolt on. I like the idea of the plenum you suggest, but without the means to create one, I'll have to aim for smaller gains with simpler mods. I'll probably port match the upper and lower manifolds as well.

Ken